Digital Telephony (Wiley Series in Telecommunications and Signal Processing)
From the reviews of the Second Edition . "The book stresses how systems operate and the rationale behind their design, rather than presenting rigorous analytical formulations . [It provides] the practicality and breadth essential to mastering the concepts of modern communications systems." -Telecommunication Journal In this expanded new edition of his bestselling book, telephony expert John Bellamy continues to provide telecommunications engineers with practical, comprehensive coverage of all aspects of digital telephone systems, while addressing the rapid changes the field has seen in recent years. Bellamy discusses the near-complete conversion to digital technology in telephone networks worldwide, examines both existing and emerging technologies, and explores the intricacies of carrying voice over data networks as well as the use of telephone networks for carrying data for Internet access. He emphasizes system design, implementation, and application, but also correlates the practice to communications theory. With 30 percent new material, Digital Telephony, Third Edition features: Clear explanations on how to overcome problems associated with the replacement of old analog technology with new digital technology A new chapter on digital mobile telephone technology New material on how, data networks support voice communication A new chapter on digital subscriber access technologies More than 300 graphs illustrating concepts Examples from the U.S. network as well as ITU public telephone networks An Instructor's Manual presenting detailed solutions to all the problems in the book is available from the Wiley editorial department.
Why Read This Book
You should read this book if you need a practical, system-level picture of how modern telephone networks work — from PCM/TDM transport to voice codecs and signaling — rather than only mathematical treatments. It explains design rationales, implementation trade-offs, and real-world issues (echo, jitter, synchronization, quality) that you'll confront when working on voice communications systems.
Who Will Benefit
Telecommunications and voice-systems engineers, systems integrators, and graduate students who need a practical, end-to-end understanding of digital telephony and voice-coding in networked systems.
Level: Intermediate — Prerequisites: Basic signals & systems and digital communications concepts (sampling, filtering, bit error concepts) plus familiarity with general networking terminology.
Key Takeaways
- Explain the principles and implementation of PCM and TDM hierarchies (T1/E1, DS/PCM framing)
- Describe common voice-coding methods and codecs (PCM, μ-law/A-law, ADPCM, CELP-style vocoders) and their trade-offs
- Analyze network-level issues affecting voice quality: jitter, latency, echo, synchronization and QoS considerations
- Interpret telephony signaling and control architectures (subscriber interfaces, SS7, ISDN concepts) and switching basics
- Assess transmission and multiplexing technologies used in telephony (digital trunks, fiber transport, E-carrier)
- Apply practical troubleshooting and design guidance for deploying digital voice links and interconnecting legacy and packet systems
Topics Covered
- Overview and evolution of telephony systems
- Basic voice signal characteristics and PCM fundamentals
- Pulse code modulation, quantization, and companding (μ-law/A-law)
- Time-division multiplexing and digital hierarchy (T1/E1, DSn)
- Digital transmission systems, framing and synchronization
- Voice coding and compression (ADPCM, CELP and low-rate coders)
- Echo, echo control and line impairments
- Switching architectures and network design
- Signaling systems and control (SS7, ISDN concepts)
- Transmission media and trunk technology (fiber, microwave, digital trunks)
- Quality, performance metrics and maintenance/test practices
- Emerging technologies and packetization issues (ATM/early packet telephony concepts)
Languages, Platforms & Tools
How It Compares
More system- and standards-oriented than DSP-focused texts such as "Speech and Audio Signal Processing" (Gold & Morgan); compared with Proakis' "Digital Communications" it is far more application/practical and less theoretical.
